Storage System Having Cross Node Data Redundancy and Method and Computer Readable Medium for Same

1. A method, comprising: providing data redundancy across a plurality of disk drives at a node, wherein the plurality of disk drives and the node are included in a first level disk array; and forming, by a cross-node manager, a second level disk array from a first plurality of a disk drives of the node and second plurality of disk drives from another node of the plurality of nodes.

2. The method of claim 1 , wherein the data redundancy includes an architecture selected from the group consisting of RAID5 and RAID6.

3. The method of claim 1 , wherein a data layout across the first plurality of disk drives includes the architecture RAID0.

4. The method of claim 1 , further comprising subdividing the first level disk array of the node into a plurality of level-2 disk drives, and wherein said second level disk array includes a multiple of the plurality of level-2 disk drives of the node.

5. The method of claim 1 , further comprising subdividing the second level disk array into a plurality of level-3 disk drives and making the level-3 disks available for providing data redundancy across a geographical site.

6. The method of claim 1 , further comprising restoring data using the second level disk array responsive to failure of the node.

7. The method of claim 6 , wherein said failure of a node includes temporary unavailability of the node.

8. The method of claim 1 , further comprising receiving an indication of an additional node having additional disk drives, scanning the second level disk array to identify selected second level disks of the second level disk array for migration, and migrating the selected disk drives to the additional node using online mirroring and copying.

9. The method of claim 8 , wherein the second level disk array has a width, further comprising generating another second level disk array having a width larger than the width of the first-named second level disk array.

10. The method of claim 1 , further comprising receiving an indication of unavailability of a particular disk of the second level disk array, and setting bits of a bitmap corresponding to locations of the particular disk.

11. The method of claim 10 , further comprising receiving an indication of restoration of the particular disk of the second level disk array, scanning the bitmap, and rebuilding only the portions of the disk array corresponding to certain bits of the bitmap.

12. A non-transitory computer readable medium comprising instructions that when read by a processor perform: providing data redundancy across a plurality of disk drives at a node, wherein the plurality of disk drives and the node are included in a first level disk array; and forming, by a cross-node manager, a second level disk array from a first plurality of a disk drives of the node and second plurality of disk drives from another node of the plurality of nodes.

13. The method of claim 12 , wherein the data redundancy includes an architecture selected from the group consisting of RAID5 and RAID6.

14. The method of claim 12 , wherein a data layout across the first plurality of disk drives includes the architecture RAID0.

15. The method of claim 12 , further comprising subdividing the first level disk array of the node into a plurality of level-2 disk drives, and wherein said second level disk array includes a multiple of the plurality of level-2 disk drives of the node.

16. The method of claim 12 , further comprising subdividing the second level disk array into a plurality of level-3 disk drives and making the level-3 disks available for providing data redundancy across a geographical site.

17. The method of claim 12 , further comprising restoring data using the second level disk array responsive to failure of the node.

18. The method of claim 17 , wherein said failure of a node includes temporary unavailability of the node.

19. The method of claim 12 , further comprising receiving an indication of an additional node having additional disk drives, scanning the second level disk array to identify selected second level disks of the second level disk array for migration, and migrating the selected disk drives to the additional node using online mirroring and copying.

20. The method of claim 12 , wherein the second level disk array has a width, further comprising generating another second level disk array having a width larger than the width of the first-named second level disk array.